to evaluate whether ivus-guided drug-eluting stent (des) implantation leads to better clinical outcomes compared to conventional angiography in the treatment of chronic complete occlusion (cto) disease.

Conditions: Chronic Total Occlusion of Coronary Artery

Summary: this study aims to evaluate the treatment of chronic total occlusion (cto) disease. whether intravascular ultrasonography (ivus) guiding the implantation of drug-eluting stents (des) will provide better long-term clinical outcomes compared with conventional angiography

the study was a prospective, multicenter, open-label, two-arm, 1:1 randomized controlled, well-designed clinical study. according to the sample size calculation, a total of 1448 patients with primary cto lesions were required to participate in the study after the guide wire successfully passed through the lesion (defined as: angiographic indication that the guide wire successfully passed through the cto lesion and reached the distal true lumen). the study will be conducted at no more than 45research centers. with competitive enrolment, a maximum of 500 patients can be enrolled at each center or until the study is completed, whichever comes first. it is recommended that each center enroll at least 20 patients.

Eligibility criteria:
clinical inclusion criteria: 1. at least 18 years old 2. subjects will understand the test requirements, treatment and surgery, and can provide written informed consent 3. subjects with clinical symptoms of ischemic heart disease or evidence of myocardial ischemia associated with cto target vessels and scheduled to undergo percutaneous coronary intervention (pci) 4. subjects will receive percutaneous coronary intervention 5. subjects are willing to accept all treatment and follow-up evaluations required by the protocol inclusion criteria for angiography: 1. primary coronary artery cto lesion with visible collateral circulation 2. estimation of the time to complete occlusion (timi grade 0) ≥3 months based on clinical history and/or comparison with historical angiography or ecg 3. it is suitable for target lesions of 2.25-4.0mm stent implantation 4. the length of cto lesion should be greater than 20mm clinical exclusion criteria: 1. pregnant and lactating women 2. severe coronary artery disease, not suitable for pci 3. patients with acute myocardial infarction less than 7 days 4. long-term contraindications to dapt (at least 1 year) 5. known renal insufficiency.20 ml/min / 1.73 ㎡) 6. left ventricular ejection fraction \&lt;35% or cardiogenic shock 7. the icd implanted/crt 8. severe bleeding or stroke within 6 months 9. have a history of allergy to iodine contrast agents or any known allergy to clopidogrel, ticagrelor, aspirin, or heparin 10. subjects have been diagnosed or suspected of liver disease, including laboratory evidence of hepatitis 11. valvular heart disease significantly affecting hemodynamics, hypertrophic cardiomyopathy, restrictive cardiomyopathy, or congenital heart disease 12. diseases that researchers believe may seriously harm patients, such as cancer and mental illness;or the patient's life expectancy is less than one year and the follow-up cannot be completed;or other conditions that researchers think might have confounded the results 13. participate in any other ongoing trial or intend to participate in another clinical trial of a drug or device within 12 months after baseline surgery angiographic exclusion criteria: 1. the target lesion is located in the left main artery 2. no visible collateral circulation in cto lesions 3. target lesion is venous or arterial bypass graft 4. the target vessel occlusion time (timi grade 0) \< 3 months can be determined

Keywords: timi flow = grade 0 coronary artery disease with a duration greater than 3 months.